CLINICAL RESEARCH: COAGULATION
The Risk of Hemorrhage Among Patients With Warfarin-Associated Coagulopathy
David A. Garcia, MD*,*,
Susan Regan, PhD ,
Mark Crowther, MD and
Elaine M. Hylek, MD, MPH
* Department of Medicine, University of New Mexico, Albuquerque, New Mexico
Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
Department of Medicine, McMaster University, Hamilton, Ontario, Canada
Department of Medicine, General Internal Medicine Research Unit, Boston University School of Medicine, Boston Medical Center, Boston, Massachusetts
Manuscript received July 1, 2005;
revised manuscript received September 8, 2005,
accepted September 13, 2005.
* Reprint requests and correspondence: Dr. David A. Garcia, 2211 Lomas Northeast, MSC10 5550, Albuquerque, New Mexico 87131. (Email: davgarcia{at}salud.unm.edu).
OBJECTIVES: Among warfarin-treated patients with international normalized ratio (INR) >5, we sought to determine the risk of major bleeding within 30 days.
BACKGROUND: For warfarin-treated patients, the risk of bleeding increases as the INR rises, particularly if the INR exceeds 4. The 30-day risk of hemorrhage among outpatients with excessively prolonged INR values is unknown.
METHODS: To assess anticoagulation care in the U.S., a cohort of 6,761 patients taking warfarin was prospectively assembled from 101 participating sites (43% were community-based cardiology practices). From this cohort, 1,104 patients were identified with a first episode of INR >5.
RESULTS: A total of 979 met eligibility criteria; complete follow-up information was available for 976 (99.7%). Ninety-six percent (n = 937) of patients had an INR value between 5 and 9; 80% of INR values were <7. Thirteen patients (1.3%) experienced major hemorrhage during the 30-day follow-up period; among patients whose INR was >5 and <9, 0.96% experienced major hemorrhage. None of the bleeding events was fatal. Intervention with vitamin K was uncommon (8.7%). Warfarin doses were withheld for the majority of patients. Fifty percent of patients who were managed conservatively and retested on day 4 or 5 had an INR of 2.0 or less.
CONCLUSIONS: For warfarin-treated outpatients presenting with an INR >5 and <9, the 30-day risk of major bleeding is low (0.96%). Intervention with vitamin K among asymptomatic patients presenting with an INR <9 is not routine practice in the U.S.
This article has been cited by other articles:
|
|
|
|
 
A. J. Rose, A. Ozonoff, R. W. Grant, L. E. Henault, and E. M. Hylek
Epidemiology of Subtherapeutic Anticoagulation in the United States
Circ Cardiovasc Qual Outcomes,
November 1, 2009;
2(6):
591 - 597.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. A. Crowther and D. Garcia
Vitamin K to Correct Overanticoagulation
Ann Intern Med,
September 15, 2009;
151(6):
435 - 435.
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. A. Crowther, W. Ageno, D. Garcia, L. Wang, D. M. Witt, N. P. Clark, M. D. Blostein, S. R. Kahn, S. K. Vesely, S. Schulman, et al.
Oral Vitamin K Versus Placebo to Correct Excessive Anticoagulation in Patients Receiving Warfarin: A Randomized Trial
Ann Intern Med,
March 3, 2009;
150(5):
293 - 300.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M.-J. Kim, S.-M. Huang, U. A. Meyer, A. Rahman, and L. J. Lesko
A Regulatory Science Perspective on Warfarin Therapy: A Pharmacogenetic Opportunity
J. Clin. Pharmacol.,
February 1, 2009;
49(2):
138 - 146.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Ansell, J. Hirsh, E. Hylek, A. Jacobson, M. Crowther, and G. Palareti
Pharmacology and Management of the Vitamin K Antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)
Chest,
June 1, 2008;
133(6_suppl):
160S - 198S.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. Dentali and M. A. Crowther
Management of Excessive Anticoagulant Effect Due to Vitamin K Antagonists
Hematology,
January 1, 2008;
2008(1):
266 - 270.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
